The invention relates to a screw connection device for connecting two pipes, comprising two pipes with flanged pipe ends, a bolt, a nut and a spacer.
Screw connection devices of the aforementioned type are fundamentally known from the existing literature. EP 2 642 172 A1 teaches of a screw connection device for connecting two flanged pipe ends of two pipes, in particular for brake lines. The device further comprises a nut and a bolt, wherein a spacer serves as a fluid-tight coupling for the two pipes inside a coupling piece designed as a nut. The second pipe is tightened down by means of the bolt, by means of which a seal is ensured. In a pre-assembly the first pipe as well as the spacer are inserted into the nut, and first connected to the second pipe during assembly, possibly at another location. In order to ensure that the spacer does not fall out of the nut during a possible transport between the pre-assembly and the assembly, according to the aforementioned document, it is retained in the receiving space by means of a thread profile of the inner thread of the nut, extending through the receiving space. The spacer can be screwed into the inner thread of the nut by means of the outer thread provided thereon, until it no longer engages with said inner thread, and instead is located in a section of the receiving space having no thread. It is held securely in place there by the inner thread of the nut, extending through the receiving space, thus significantly reducing the difficulties encountered during the assembly. It is, however, disadvantageous that, according to this solution, the spacer must be provided with an outer thread, which in turn increases the complexity. Moreover, the simple screwing of the spacer therein also results in a certain complexity.
DE 10 107 246 C5 makes known the production of a spacer without an outer thread, which is nevertheless retained securely in a receiving space. This is obtained by means of a ring, on the edge of the receiving space having no thread, extending into the receiving space, which is produced after insertion of the first pipe and the spacer by means of stamping in an axial direction. In the longitudinal section it is apparent that the stamping results in a ring, having a detent-like shaped cross-section, and on the whole is quite delicate. In order to produce such a ring, the stamping tool must be precisely oriented, thus increasing the complexity. Even a very slight carelessness in orienting the stamping tool leads to breaks, or gaps in the ring, resulting in an increased reject rate.
For this reason, the invention addresses the technical problem of providing a screw connection device of the type specified in the introduction, distinguished in that it can be reliably assembled, and which is furthermore easy to produce.